There are variety of compounds releasing unpleasant smell to the surrounding in the living environment and even harmful to human health, which compounds such as ammonia, amine, hydrogen sulfide, mercaptan, short chain fatty acid, aldehyde, etc. are typical compounds relate to stench in the kitchen, toilet, basement and car. At present, there has developed many types of deodorant to deodorize or absorb these stenches. The deodorant supplied in the market usually covers up the stench by releasing air freshener, proceeding physical absorption and having a chemical reaction with stench compounds. The substance used as a absorbent including activated carbon, zeolite, cyclodextrin, bentonite, etc. The material having chemical reaction with stench compounds usually including a chlorine dioxide, a hypochlorous acid, an ozone and a polymer contains function groups, and these materials decompose the stench compounds by oxidation, reduction or neutralization.
The common photocatalyst is nano-titanium dioxide photocatalyst since 1990s, when the nano-titanium dioxide photocatalyst exposed to light, it will produce photocatalytic reaction continuously, and produces a hydroxyl radical having function of decomposing organic matter, and inhibiting virus activity, etc., but does not consume itself The scientist applies the nano-titanium dioxide photocatalyst which results in good effect in air purification, antibiotic, deodorization, sterilization and anti-mold. However, the light wavelength absorbed by common photocatalyst usually is UV or visible light. Therefore, in response to diverse demands, it requires a photocatalyst capable of absorbing visible light and/or UV, and arbitrarily regulating the absorption of light in the wavelength range.
U.S. Pat. No. 5,690,922 discloses a deodorizing fiber, which contains a phosphorus-containing tetravalent metal, a hydroxide-containing divalent metal and a reactive oxygen species produced by exposing to light, and served as a photocatalyst of the photo-oxidation catalyst. The photocatalyst is composed of a variety of light semiconductors, and can be a metal or a nonmetal including sulfur-containing semiconductor, chalcogenide compounds, oxygen-containing semiconductor, etc., where the deodorant fiber has deodorant effect against acidic, alkaline and neutral stench molecular under the sunlight, fluorescent lamp and UV lamp. However, the photocatalyst is formed by two or three combinations of metals, and does not have a function of regulating the absorption of light wavelength range.
The conduction band and valence band position of the fixed composition of the photocatalyst, such as titanium dioxide, is fixed. The conduction band of the semiconductor plays the deliver role for a negatively charge, the valence band of the semiconductor plays the deliver role for a positive charge, and the different position of conduction band and valence bond will affect different chemical reactions (because of the difference of its reaction potential, for example the more difficult response to restore, the higher conduction band position is required). The physical and chemical properties of solid solution photocatalyst can be tuned by changing its component. Hence, the position and the range of the conduction band and valence band of the solid solution photocatalyst can be regulated. Usually the high conductivity photocatalyst and the low conduction band photocatalyst are synthesized to form a middle conduction band photocatalyst, and valence band is formed by the same way.
Therefore, it becomes an important issue for seeking a photocatalyst capable of controlling the conduction band position, valence band position, conduction band range and/or valence band range, so that the photocatalyst can regulate the wavelength range of the absorbed light.
It is therefore attempted by the applicant to deal with the aforementioned situation encountered in the prior art.